The company - which recently hit 200m members - also offered a bullish forecast for the first quarter of 2013, with revenue projected at between $305 million and $310 million, above most analyst estimates of $301m.

While the likes of Facebook and Zynga have struggled to live up to the social media hype with investors, LinkedIn has now beat analyst estimates for seven straight quarters.

LinkedIn shares were up 9% in after-hours trading on the positive results, at $135, and have doubled over the past year.

"We exited 2011 having successfully revamped our underlying development infrastructure. Based on that investment, we said that 2012 would be a year of accelerated product innovation, and it was," said LinkedIn in a statement.

"The products we delivered throughout the year drove member engagement and financial results to record levels in the fourth quarter."

In the fourth quarter of 2012, earnings from "talent solutions" recruitment products at LinkedIn increased by 90% year-on-year to $161m, totalling 53% of all revenue in the three months.

Julia Bramble, a director of social media experts Bramble Buzz, said LinkedIn has excelled as it "allows businesses the world over to start the conversations that matter".

"These strong results from LinkedIn will come as no surprise to anyone who uses the platform regularly," she said.

"In recent months, there has been a huge increase in engagement on LinkedIn. When people write an update, no longer are they just firing it off into the aether, but other people now respond and comment, and real discussion ensues.

"The world has woken up to the fact that people on LinkedIn are there to do business, so they are already in the right context and mindset to be marketed to. You can't say the same of Twitter and Facebook, although it is undoubtedly the huge success of these platforms that has driven this upsurge in interest in LinkedIn."